"VW has been talking for a long time about its L1 concept, so called because it uses a measly 1 liter of gasoline to go 100 km... Of course, the amazing mileage comes at a price... The single passenger actually sits behind the driver, like in a small airplane. The tiny engine will only get the car up to about 75 mph and, as such, VW doesn't expect to sell a lot of these vehicles. Safety concerns might also keep the car from being a best seller. But, since it does have four wheels, it will have to meet all of the normal safety regulations for cars. VW will continue to release details on the car, but it is firm that this vehicle will be produced by 2010."It will compete with the three-wheeled 300 mile-per-gallon Aptera. "The Aptera is fuel-efficient because it is extremely light, and it keeps itself so light in a few ways. First, the engine is tiny, one cylinder, but that's OK, because it's only ever used to charge the batteries. It also stays light by doing away with one of the wheels. This also helps because then, according to American safety regulations, it is technically a motorcycle, and so doesn't have to jump through any of the normal safety hoops."
Since they appear to be hybrid motorcycle-cars, these vehicles are unlikely to replace current cars en masse, but they will fill a niche. It will depend on whether a driver or family can save enough on fuel to justify one of these as a second vehicle. I drive about 16,000 miles per year, about 8,000 of that city driving suitable for a minicar. At my current 20 mpg city, that's 400 gallons per year; switching to a 200 mpg car would cut gas consumption to 40 gallons, saving 360 gallons. At $4/gallon that saves $1,440 per year - not enough to justify a $20K car in strict economic terms. But gas may go to $8/gallon, or the car prices may come down. Things could get interesting...